Question

What is Ether in relativity?

Answer 1

1. Relativity is a theorem, formulated by Albert Einstein, which states space and time are relative and all motion must be relative to a frame of reference.
2. The ether is indistinguishable from ordinary matter in its roles.
3. Ether, also spelled aether, also called luminiferous ether, in physics, a theoretical universal substance believed during the 19th century to act as the medium for transmission of electromagnetic waves (e.g., light and X-rays), much as sound waves are transmitted by elastic media such as air.
4. The ether was assumed to be weightless, transparent, frictionless, undetectable chemically or physically, and literally permeating all matter and space.